Loading...
1/*
2 * linux/net/sunrpc/gss_krb5_crypto.c
3 *
4 * Copyright (c) 2000-2008 The Regents of the University of Michigan.
5 * All rights reserved.
6 *
7 * Andy Adamson <andros@umich.edu>
8 * Bruce Fields <bfields@umich.edu>
9 */
10
11/*
12 * Copyright (C) 1998 by the FundsXpress, INC.
13 *
14 * All rights reserved.
15 *
16 * Export of this software from the United States of America may require
17 * a specific license from the United States Government. It is the
18 * responsibility of any person or organization contemplating export to
19 * obtain such a license before exporting.
20 *
21 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
22 * distribute this software and its documentation for any purpose and
23 * without fee is hereby granted, provided that the above copyright
24 * notice appear in all copies and that both that copyright notice and
25 * this permission notice appear in supporting documentation, and that
26 * the name of FundsXpress. not be used in advertising or publicity pertaining
27 * to distribution of the software without specific, written prior
28 * permission. FundsXpress makes no representations about the suitability of
29 * this software for any purpose. It is provided "as is" without express
30 * or implied warranty.
31 *
32 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
33 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
34 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
35 */
36
37#include <linux/err.h>
38#include <linux/types.h>
39#include <linux/mm.h>
40#include <linux/scatterlist.h>
41#include <linux/crypto.h>
42#include <linux/highmem.h>
43#include <linux/pagemap.h>
44#include <linux/random.h>
45#include <linux/sunrpc/gss_krb5.h>
46#include <linux/sunrpc/xdr.h>
47
48#ifdef RPC_DEBUG
49# define RPCDBG_FACILITY RPCDBG_AUTH
50#endif
51
52u32
53krb5_encrypt(
54 struct crypto_blkcipher *tfm,
55 void * iv,
56 void * in,
57 void * out,
58 int length)
59{
60 u32 ret = -EINVAL;
61 struct scatterlist sg[1];
62 u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0};
63 struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
64
65 if (length % crypto_blkcipher_blocksize(tfm) != 0)
66 goto out;
67
68 if (crypto_blkcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
69 dprintk("RPC: gss_k5encrypt: tfm iv size too large %d\n",
70 crypto_blkcipher_ivsize(tfm));
71 goto out;
72 }
73
74 if (iv)
75 memcpy(local_iv, iv, crypto_blkcipher_ivsize(tfm));
76
77 memcpy(out, in, length);
78 sg_init_one(sg, out, length);
79
80 ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length);
81out:
82 dprintk("RPC: krb5_encrypt returns %d\n", ret);
83 return ret;
84}
85
86u32
87krb5_decrypt(
88 struct crypto_blkcipher *tfm,
89 void * iv,
90 void * in,
91 void * out,
92 int length)
93{
94 u32 ret = -EINVAL;
95 struct scatterlist sg[1];
96 u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0};
97 struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
98
99 if (length % crypto_blkcipher_blocksize(tfm) != 0)
100 goto out;
101
102 if (crypto_blkcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
103 dprintk("RPC: gss_k5decrypt: tfm iv size too large %d\n",
104 crypto_blkcipher_ivsize(tfm));
105 goto out;
106 }
107 if (iv)
108 memcpy(local_iv,iv, crypto_blkcipher_ivsize(tfm));
109
110 memcpy(out, in, length);
111 sg_init_one(sg, out, length);
112
113 ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length);
114out:
115 dprintk("RPC: gss_k5decrypt returns %d\n",ret);
116 return ret;
117}
118
119static int
120checksummer(struct scatterlist *sg, void *data)
121{
122 struct hash_desc *desc = data;
123
124 return crypto_hash_update(desc, sg, sg->length);
125}
126
127static int
128arcfour_hmac_md5_usage_to_salt(unsigned int usage, u8 salt[4])
129{
130 unsigned int ms_usage;
131
132 switch (usage) {
133 case KG_USAGE_SIGN:
134 ms_usage = 15;
135 break;
136 case KG_USAGE_SEAL:
137 ms_usage = 13;
138 break;
139 default:
140 return -EINVAL;
141 }
142 salt[0] = (ms_usage >> 0) & 0xff;
143 salt[1] = (ms_usage >> 8) & 0xff;
144 salt[2] = (ms_usage >> 16) & 0xff;
145 salt[3] = (ms_usage >> 24) & 0xff;
146
147 return 0;
148}
149
150static u32
151make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
152 struct xdr_buf *body, int body_offset, u8 *cksumkey,
153 unsigned int usage, struct xdr_netobj *cksumout)
154{
155 struct hash_desc desc;
156 struct scatterlist sg[1];
157 int err;
158 u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
159 u8 rc4salt[4];
160 struct crypto_hash *md5;
161 struct crypto_hash *hmac_md5;
162
163 if (cksumkey == NULL)
164 return GSS_S_FAILURE;
165
166 if (cksumout->len < kctx->gk5e->cksumlength) {
167 dprintk("%s: checksum buffer length, %u, too small for %s\n",
168 __func__, cksumout->len, kctx->gk5e->name);
169 return GSS_S_FAILURE;
170 }
171
172 if (arcfour_hmac_md5_usage_to_salt(usage, rc4salt)) {
173 dprintk("%s: invalid usage value %u\n", __func__, usage);
174 return GSS_S_FAILURE;
175 }
176
177 md5 = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
178 if (IS_ERR(md5))
179 return GSS_S_FAILURE;
180
181 hmac_md5 = crypto_alloc_hash(kctx->gk5e->cksum_name, 0,
182 CRYPTO_ALG_ASYNC);
183 if (IS_ERR(hmac_md5)) {
184 crypto_free_hash(md5);
185 return GSS_S_FAILURE;
186 }
187
188 desc.tfm = md5;
189 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
190
191 err = crypto_hash_init(&desc);
192 if (err)
193 goto out;
194 sg_init_one(sg, rc4salt, 4);
195 err = crypto_hash_update(&desc, sg, 4);
196 if (err)
197 goto out;
198
199 sg_init_one(sg, header, hdrlen);
200 err = crypto_hash_update(&desc, sg, hdrlen);
201 if (err)
202 goto out;
203 err = xdr_process_buf(body, body_offset, body->len - body_offset,
204 checksummer, &desc);
205 if (err)
206 goto out;
207 err = crypto_hash_final(&desc, checksumdata);
208 if (err)
209 goto out;
210
211 desc.tfm = hmac_md5;
212 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
213
214 err = crypto_hash_init(&desc);
215 if (err)
216 goto out;
217 err = crypto_hash_setkey(hmac_md5, cksumkey, kctx->gk5e->keylength);
218 if (err)
219 goto out;
220
221 sg_init_one(sg, checksumdata, crypto_hash_digestsize(md5));
222 err = crypto_hash_digest(&desc, sg, crypto_hash_digestsize(md5),
223 checksumdata);
224 if (err)
225 goto out;
226
227 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
228 cksumout->len = kctx->gk5e->cksumlength;
229out:
230 crypto_free_hash(md5);
231 crypto_free_hash(hmac_md5);
232 return err ? GSS_S_FAILURE : 0;
233}
234
235/*
236 * checksum the plaintext data and hdrlen bytes of the token header
237 * The checksum is performed over the first 8 bytes of the
238 * gss token header and then over the data body
239 */
240u32
241make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen,
242 struct xdr_buf *body, int body_offset, u8 *cksumkey,
243 unsigned int usage, struct xdr_netobj *cksumout)
244{
245 struct hash_desc desc;
246 struct scatterlist sg[1];
247 int err;
248 u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
249 unsigned int checksumlen;
250
251 if (kctx->gk5e->ctype == CKSUMTYPE_HMAC_MD5_ARCFOUR)
252 return make_checksum_hmac_md5(kctx, header, hdrlen,
253 body, body_offset,
254 cksumkey, usage, cksumout);
255
256 if (cksumout->len < kctx->gk5e->cksumlength) {
257 dprintk("%s: checksum buffer length, %u, too small for %s\n",
258 __func__, cksumout->len, kctx->gk5e->name);
259 return GSS_S_FAILURE;
260 }
261
262 desc.tfm = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
263 if (IS_ERR(desc.tfm))
264 return GSS_S_FAILURE;
265 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
266
267 checksumlen = crypto_hash_digestsize(desc.tfm);
268
269 if (cksumkey != NULL) {
270 err = crypto_hash_setkey(desc.tfm, cksumkey,
271 kctx->gk5e->keylength);
272 if (err)
273 goto out;
274 }
275
276 err = crypto_hash_init(&desc);
277 if (err)
278 goto out;
279 sg_init_one(sg, header, hdrlen);
280 err = crypto_hash_update(&desc, sg, hdrlen);
281 if (err)
282 goto out;
283 err = xdr_process_buf(body, body_offset, body->len - body_offset,
284 checksummer, &desc);
285 if (err)
286 goto out;
287 err = crypto_hash_final(&desc, checksumdata);
288 if (err)
289 goto out;
290
291 switch (kctx->gk5e->ctype) {
292 case CKSUMTYPE_RSA_MD5:
293 err = kctx->gk5e->encrypt(kctx->seq, NULL, checksumdata,
294 checksumdata, checksumlen);
295 if (err)
296 goto out;
297 memcpy(cksumout->data,
298 checksumdata + checksumlen - kctx->gk5e->cksumlength,
299 kctx->gk5e->cksumlength);
300 break;
301 case CKSUMTYPE_HMAC_SHA1_DES3:
302 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
303 break;
304 default:
305 BUG();
306 break;
307 }
308 cksumout->len = kctx->gk5e->cksumlength;
309out:
310 crypto_free_hash(desc.tfm);
311 return err ? GSS_S_FAILURE : 0;
312}
313
314/*
315 * checksum the plaintext data and hdrlen bytes of the token header
316 * Per rfc4121, sec. 4.2.4, the checksum is performed over the data
317 * body then over the first 16 octets of the MIC token
318 * Inclusion of the header data in the calculation of the
319 * checksum is optional.
320 */
321u32
322make_checksum_v2(struct krb5_ctx *kctx, char *header, int hdrlen,
323 struct xdr_buf *body, int body_offset, u8 *cksumkey,
324 unsigned int usage, struct xdr_netobj *cksumout)
325{
326 struct hash_desc desc;
327 struct scatterlist sg[1];
328 int err;
329 u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
330 unsigned int checksumlen;
331
332 if (kctx->gk5e->keyed_cksum == 0) {
333 dprintk("%s: expected keyed hash for %s\n",
334 __func__, kctx->gk5e->name);
335 return GSS_S_FAILURE;
336 }
337 if (cksumkey == NULL) {
338 dprintk("%s: no key supplied for %s\n",
339 __func__, kctx->gk5e->name);
340 return GSS_S_FAILURE;
341 }
342
343 desc.tfm = crypto_alloc_hash(kctx->gk5e->cksum_name, 0,
344 CRYPTO_ALG_ASYNC);
345 if (IS_ERR(desc.tfm))
346 return GSS_S_FAILURE;
347 checksumlen = crypto_hash_digestsize(desc.tfm);
348 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
349
350 err = crypto_hash_setkey(desc.tfm, cksumkey, kctx->gk5e->keylength);
351 if (err)
352 goto out;
353
354 err = crypto_hash_init(&desc);
355 if (err)
356 goto out;
357 err = xdr_process_buf(body, body_offset, body->len - body_offset,
358 checksummer, &desc);
359 if (err)
360 goto out;
361 if (header != NULL) {
362 sg_init_one(sg, header, hdrlen);
363 err = crypto_hash_update(&desc, sg, hdrlen);
364 if (err)
365 goto out;
366 }
367 err = crypto_hash_final(&desc, checksumdata);
368 if (err)
369 goto out;
370
371 cksumout->len = kctx->gk5e->cksumlength;
372
373 switch (kctx->gk5e->ctype) {
374 case CKSUMTYPE_HMAC_SHA1_96_AES128:
375 case CKSUMTYPE_HMAC_SHA1_96_AES256:
376 /* note that this truncates the hash */
377 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
378 break;
379 default:
380 BUG();
381 break;
382 }
383out:
384 crypto_free_hash(desc.tfm);
385 return err ? GSS_S_FAILURE : 0;
386}
387
388struct encryptor_desc {
389 u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
390 struct blkcipher_desc desc;
391 int pos;
392 struct xdr_buf *outbuf;
393 struct page **pages;
394 struct scatterlist infrags[4];
395 struct scatterlist outfrags[4];
396 int fragno;
397 int fraglen;
398};
399
400static int
401encryptor(struct scatterlist *sg, void *data)
402{
403 struct encryptor_desc *desc = data;
404 struct xdr_buf *outbuf = desc->outbuf;
405 struct page *in_page;
406 int thislen = desc->fraglen + sg->length;
407 int fraglen, ret;
408 int page_pos;
409
410 /* Worst case is 4 fragments: head, end of page 1, start
411 * of page 2, tail. Anything more is a bug. */
412 BUG_ON(desc->fragno > 3);
413
414 page_pos = desc->pos - outbuf->head[0].iov_len;
415 if (page_pos >= 0 && page_pos < outbuf->page_len) {
416 /* pages are not in place: */
417 int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
418 in_page = desc->pages[i];
419 } else {
420 in_page = sg_page(sg);
421 }
422 sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length,
423 sg->offset);
424 sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length,
425 sg->offset);
426 desc->fragno++;
427 desc->fraglen += sg->length;
428 desc->pos += sg->length;
429
430 fraglen = thislen & (crypto_blkcipher_blocksize(desc->desc.tfm) - 1);
431 thislen -= fraglen;
432
433 if (thislen == 0)
434 return 0;
435
436 sg_mark_end(&desc->infrags[desc->fragno - 1]);
437 sg_mark_end(&desc->outfrags[desc->fragno - 1]);
438
439 ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
440 desc->infrags, thislen);
441 if (ret)
442 return ret;
443
444 sg_init_table(desc->infrags, 4);
445 sg_init_table(desc->outfrags, 4);
446
447 if (fraglen) {
448 sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen,
449 sg->offset + sg->length - fraglen);
450 desc->infrags[0] = desc->outfrags[0];
451 sg_assign_page(&desc->infrags[0], in_page);
452 desc->fragno = 1;
453 desc->fraglen = fraglen;
454 } else {
455 desc->fragno = 0;
456 desc->fraglen = 0;
457 }
458 return 0;
459}
460
461int
462gss_encrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
463 int offset, struct page **pages)
464{
465 int ret;
466 struct encryptor_desc desc;
467
468 BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
469
470 memset(desc.iv, 0, sizeof(desc.iv));
471 desc.desc.tfm = tfm;
472 desc.desc.info = desc.iv;
473 desc.desc.flags = 0;
474 desc.pos = offset;
475 desc.outbuf = buf;
476 desc.pages = pages;
477 desc.fragno = 0;
478 desc.fraglen = 0;
479
480 sg_init_table(desc.infrags, 4);
481 sg_init_table(desc.outfrags, 4);
482
483 ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc);
484 return ret;
485}
486
487struct decryptor_desc {
488 u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
489 struct blkcipher_desc desc;
490 struct scatterlist frags[4];
491 int fragno;
492 int fraglen;
493};
494
495static int
496decryptor(struct scatterlist *sg, void *data)
497{
498 struct decryptor_desc *desc = data;
499 int thislen = desc->fraglen + sg->length;
500 int fraglen, ret;
501
502 /* Worst case is 4 fragments: head, end of page 1, start
503 * of page 2, tail. Anything more is a bug. */
504 BUG_ON(desc->fragno > 3);
505 sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length,
506 sg->offset);
507 desc->fragno++;
508 desc->fraglen += sg->length;
509
510 fraglen = thislen & (crypto_blkcipher_blocksize(desc->desc.tfm) - 1);
511 thislen -= fraglen;
512
513 if (thislen == 0)
514 return 0;
515
516 sg_mark_end(&desc->frags[desc->fragno - 1]);
517
518 ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
519 desc->frags, thislen);
520 if (ret)
521 return ret;
522
523 sg_init_table(desc->frags, 4);
524
525 if (fraglen) {
526 sg_set_page(&desc->frags[0], sg_page(sg), fraglen,
527 sg->offset + sg->length - fraglen);
528 desc->fragno = 1;
529 desc->fraglen = fraglen;
530 } else {
531 desc->fragno = 0;
532 desc->fraglen = 0;
533 }
534 return 0;
535}
536
537int
538gss_decrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
539 int offset)
540{
541 struct decryptor_desc desc;
542
543 /* XXXJBF: */
544 BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
545
546 memset(desc.iv, 0, sizeof(desc.iv));
547 desc.desc.tfm = tfm;
548 desc.desc.info = desc.iv;
549 desc.desc.flags = 0;
550 desc.fragno = 0;
551 desc.fraglen = 0;
552
553 sg_init_table(desc.frags, 4);
554
555 return xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
556}
557
558/*
559 * This function makes the assumption that it was ultimately called
560 * from gss_wrap().
561 *
562 * The client auth_gss code moves any existing tail data into a
563 * separate page before calling gss_wrap.
564 * The server svcauth_gss code ensures that both the head and the
565 * tail have slack space of RPC_MAX_AUTH_SIZE before calling gss_wrap.
566 *
567 * Even with that guarantee, this function may be called more than
568 * once in the processing of gss_wrap(). The best we can do is
569 * verify at compile-time (see GSS_KRB5_SLACK_CHECK) that the
570 * largest expected shift will fit within RPC_MAX_AUTH_SIZE.
571 * At run-time we can verify that a single invocation of this
572 * function doesn't attempt to use more the RPC_MAX_AUTH_SIZE.
573 */
574
575int
576xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen)
577{
578 u8 *p;
579
580 if (shiftlen == 0)
581 return 0;
582
583 BUILD_BUG_ON(GSS_KRB5_MAX_SLACK_NEEDED > RPC_MAX_AUTH_SIZE);
584 BUG_ON(shiftlen > RPC_MAX_AUTH_SIZE);
585
586 p = buf->head[0].iov_base + base;
587
588 memmove(p + shiftlen, p, buf->head[0].iov_len - base);
589
590 buf->head[0].iov_len += shiftlen;
591 buf->len += shiftlen;
592
593 return 0;
594}
595
596static u32
597gss_krb5_cts_crypt(struct crypto_blkcipher *cipher, struct xdr_buf *buf,
598 u32 offset, u8 *iv, struct page **pages, int encrypt)
599{
600 u32 ret;
601 struct scatterlist sg[1];
602 struct blkcipher_desc desc = { .tfm = cipher, .info = iv };
603 u8 data[GSS_KRB5_MAX_BLOCKSIZE * 2];
604 struct page **save_pages;
605 u32 len = buf->len - offset;
606
607 if (len > ARRAY_SIZE(data)) {
608 WARN_ON(0);
609 return -ENOMEM;
610 }
611
612 /*
613 * For encryption, we want to read from the cleartext
614 * page cache pages, and write the encrypted data to
615 * the supplied xdr_buf pages.
616 */
617 save_pages = buf->pages;
618 if (encrypt)
619 buf->pages = pages;
620
621 ret = read_bytes_from_xdr_buf(buf, offset, data, len);
622 buf->pages = save_pages;
623 if (ret)
624 goto out;
625
626 sg_init_one(sg, data, len);
627
628 if (encrypt)
629 ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
630 else
631 ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, len);
632
633 if (ret)
634 goto out;
635
636 ret = write_bytes_to_xdr_buf(buf, offset, data, len);
637
638out:
639 return ret;
640}
641
642u32
643gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
644 struct xdr_buf *buf, int ec, struct page **pages)
645{
646 u32 err;
647 struct xdr_netobj hmac;
648 u8 *cksumkey;
649 u8 *ecptr;
650 struct crypto_blkcipher *cipher, *aux_cipher;
651 int blocksize;
652 struct page **save_pages;
653 int nblocks, nbytes;
654 struct encryptor_desc desc;
655 u32 cbcbytes;
656 unsigned int usage;
657
658 if (kctx->initiate) {
659 cipher = kctx->initiator_enc;
660 aux_cipher = kctx->initiator_enc_aux;
661 cksumkey = kctx->initiator_integ;
662 usage = KG_USAGE_INITIATOR_SEAL;
663 } else {
664 cipher = kctx->acceptor_enc;
665 aux_cipher = kctx->acceptor_enc_aux;
666 cksumkey = kctx->acceptor_integ;
667 usage = KG_USAGE_ACCEPTOR_SEAL;
668 }
669 blocksize = crypto_blkcipher_blocksize(cipher);
670
671 /* hide the gss token header and insert the confounder */
672 offset += GSS_KRB5_TOK_HDR_LEN;
673 if (xdr_extend_head(buf, offset, kctx->gk5e->conflen))
674 return GSS_S_FAILURE;
675 gss_krb5_make_confounder(buf->head[0].iov_base + offset, kctx->gk5e->conflen);
676 offset -= GSS_KRB5_TOK_HDR_LEN;
677
678 if (buf->tail[0].iov_base != NULL) {
679 ecptr = buf->tail[0].iov_base + buf->tail[0].iov_len;
680 } else {
681 buf->tail[0].iov_base = buf->head[0].iov_base
682 + buf->head[0].iov_len;
683 buf->tail[0].iov_len = 0;
684 ecptr = buf->tail[0].iov_base;
685 }
686
687 memset(ecptr, 'X', ec);
688 buf->tail[0].iov_len += ec;
689 buf->len += ec;
690
691 /* copy plaintext gss token header after filler (if any) */
692 memcpy(ecptr + ec, buf->head[0].iov_base + offset,
693 GSS_KRB5_TOK_HDR_LEN);
694 buf->tail[0].iov_len += GSS_KRB5_TOK_HDR_LEN;
695 buf->len += GSS_KRB5_TOK_HDR_LEN;
696
697 /* Do the HMAC */
698 hmac.len = GSS_KRB5_MAX_CKSUM_LEN;
699 hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len;
700
701 /*
702 * When we are called, pages points to the real page cache
703 * data -- which we can't go and encrypt! buf->pages points
704 * to scratch pages which we are going to send off to the
705 * client/server. Swap in the plaintext pages to calculate
706 * the hmac.
707 */
708 save_pages = buf->pages;
709 buf->pages = pages;
710
711 err = make_checksum_v2(kctx, NULL, 0, buf,
712 offset + GSS_KRB5_TOK_HDR_LEN,
713 cksumkey, usage, &hmac);
714 buf->pages = save_pages;
715 if (err)
716 return GSS_S_FAILURE;
717
718 nbytes = buf->len - offset - GSS_KRB5_TOK_HDR_LEN;
719 nblocks = (nbytes + blocksize - 1) / blocksize;
720 cbcbytes = 0;
721 if (nblocks > 2)
722 cbcbytes = (nblocks - 2) * blocksize;
723
724 memset(desc.iv, 0, sizeof(desc.iv));
725
726 if (cbcbytes) {
727 desc.pos = offset + GSS_KRB5_TOK_HDR_LEN;
728 desc.fragno = 0;
729 desc.fraglen = 0;
730 desc.pages = pages;
731 desc.outbuf = buf;
732 desc.desc.info = desc.iv;
733 desc.desc.flags = 0;
734 desc.desc.tfm = aux_cipher;
735
736 sg_init_table(desc.infrags, 4);
737 sg_init_table(desc.outfrags, 4);
738
739 err = xdr_process_buf(buf, offset + GSS_KRB5_TOK_HDR_LEN,
740 cbcbytes, encryptor, &desc);
741 if (err)
742 goto out_err;
743 }
744
745 /* Make sure IV carries forward from any CBC results. */
746 err = gss_krb5_cts_crypt(cipher, buf,
747 offset + GSS_KRB5_TOK_HDR_LEN + cbcbytes,
748 desc.iv, pages, 1);
749 if (err) {
750 err = GSS_S_FAILURE;
751 goto out_err;
752 }
753
754 /* Now update buf to account for HMAC */
755 buf->tail[0].iov_len += kctx->gk5e->cksumlength;
756 buf->len += kctx->gk5e->cksumlength;
757
758out_err:
759 if (err)
760 err = GSS_S_FAILURE;
761 return err;
762}
763
764u32
765gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
766 u32 *headskip, u32 *tailskip)
767{
768 struct xdr_buf subbuf;
769 u32 ret = 0;
770 u8 *cksum_key;
771 struct crypto_blkcipher *cipher, *aux_cipher;
772 struct xdr_netobj our_hmac_obj;
773 u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN];
774 u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN];
775 int nblocks, blocksize, cbcbytes;
776 struct decryptor_desc desc;
777 unsigned int usage;
778
779 if (kctx->initiate) {
780 cipher = kctx->acceptor_enc;
781 aux_cipher = kctx->acceptor_enc_aux;
782 cksum_key = kctx->acceptor_integ;
783 usage = KG_USAGE_ACCEPTOR_SEAL;
784 } else {
785 cipher = kctx->initiator_enc;
786 aux_cipher = kctx->initiator_enc_aux;
787 cksum_key = kctx->initiator_integ;
788 usage = KG_USAGE_INITIATOR_SEAL;
789 }
790 blocksize = crypto_blkcipher_blocksize(cipher);
791
792
793 /* create a segment skipping the header and leaving out the checksum */
794 xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN,
795 (buf->len - offset - GSS_KRB5_TOK_HDR_LEN -
796 kctx->gk5e->cksumlength));
797
798 nblocks = (subbuf.len + blocksize - 1) / blocksize;
799
800 cbcbytes = 0;
801 if (nblocks > 2)
802 cbcbytes = (nblocks - 2) * blocksize;
803
804 memset(desc.iv, 0, sizeof(desc.iv));
805
806 if (cbcbytes) {
807 desc.fragno = 0;
808 desc.fraglen = 0;
809 desc.desc.info = desc.iv;
810 desc.desc.flags = 0;
811 desc.desc.tfm = aux_cipher;
812
813 sg_init_table(desc.frags, 4);
814
815 ret = xdr_process_buf(&subbuf, 0, cbcbytes, decryptor, &desc);
816 if (ret)
817 goto out_err;
818 }
819
820 /* Make sure IV carries forward from any CBC results. */
821 ret = gss_krb5_cts_crypt(cipher, &subbuf, cbcbytes, desc.iv, NULL, 0);
822 if (ret)
823 goto out_err;
824
825
826 /* Calculate our hmac over the plaintext data */
827 our_hmac_obj.len = sizeof(our_hmac);
828 our_hmac_obj.data = our_hmac;
829
830 ret = make_checksum_v2(kctx, NULL, 0, &subbuf, 0,
831 cksum_key, usage, &our_hmac_obj);
832 if (ret)
833 goto out_err;
834
835 /* Get the packet's hmac value */
836 ret = read_bytes_from_xdr_buf(buf, buf->len - kctx->gk5e->cksumlength,
837 pkt_hmac, kctx->gk5e->cksumlength);
838 if (ret)
839 goto out_err;
840
841 if (memcmp(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) {
842 ret = GSS_S_BAD_SIG;
843 goto out_err;
844 }
845 *headskip = kctx->gk5e->conflen;
846 *tailskip = kctx->gk5e->cksumlength;
847out_err:
848 if (ret && ret != GSS_S_BAD_SIG)
849 ret = GSS_S_FAILURE;
850 return ret;
851}
852
853/*
854 * Compute Kseq given the initial session key and the checksum.
855 * Set the key of the given cipher.
856 */
857int
858krb5_rc4_setup_seq_key(struct krb5_ctx *kctx, struct crypto_blkcipher *cipher,
859 unsigned char *cksum)
860{
861 struct crypto_hash *hmac;
862 struct hash_desc desc;
863 struct scatterlist sg[1];
864 u8 Kseq[GSS_KRB5_MAX_KEYLEN];
865 u32 zeroconstant = 0;
866 int err;
867
868 dprintk("%s: entered\n", __func__);
869
870 hmac = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
871 if (IS_ERR(hmac)) {
872 dprintk("%s: error %ld, allocating hash '%s'\n",
873 __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name);
874 return PTR_ERR(hmac);
875 }
876
877 desc.tfm = hmac;
878 desc.flags = 0;
879
880 err = crypto_hash_init(&desc);
881 if (err)
882 goto out_err;
883
884 /* Compute intermediate Kseq from session key */
885 err = crypto_hash_setkey(hmac, kctx->Ksess, kctx->gk5e->keylength);
886 if (err)
887 goto out_err;
888
889 sg_init_table(sg, 1);
890 sg_set_buf(sg, &zeroconstant, 4);
891
892 err = crypto_hash_digest(&desc, sg, 4, Kseq);
893 if (err)
894 goto out_err;
895
896 /* Compute final Kseq from the checksum and intermediate Kseq */
897 err = crypto_hash_setkey(hmac, Kseq, kctx->gk5e->keylength);
898 if (err)
899 goto out_err;
900
901 sg_set_buf(sg, cksum, 8);
902
903 err = crypto_hash_digest(&desc, sg, 8, Kseq);
904 if (err)
905 goto out_err;
906
907 err = crypto_blkcipher_setkey(cipher, Kseq, kctx->gk5e->keylength);
908 if (err)
909 goto out_err;
910
911 err = 0;
912
913out_err:
914 crypto_free_hash(hmac);
915 dprintk("%s: returning %d\n", __func__, err);
916 return err;
917}
918
919/*
920 * Compute Kcrypt given the initial session key and the plaintext seqnum.
921 * Set the key of cipher kctx->enc.
922 */
923int
924krb5_rc4_setup_enc_key(struct krb5_ctx *kctx, struct crypto_blkcipher *cipher,
925 s32 seqnum)
926{
927 struct crypto_hash *hmac;
928 struct hash_desc desc;
929 struct scatterlist sg[1];
930 u8 Kcrypt[GSS_KRB5_MAX_KEYLEN];
931 u8 zeroconstant[4] = {0};
932 u8 seqnumarray[4];
933 int err, i;
934
935 dprintk("%s: entered, seqnum %u\n", __func__, seqnum);
936
937 hmac = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
938 if (IS_ERR(hmac)) {
939 dprintk("%s: error %ld, allocating hash '%s'\n",
940 __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name);
941 return PTR_ERR(hmac);
942 }
943
944 desc.tfm = hmac;
945 desc.flags = 0;
946
947 err = crypto_hash_init(&desc);
948 if (err)
949 goto out_err;
950
951 /* Compute intermediate Kcrypt from session key */
952 for (i = 0; i < kctx->gk5e->keylength; i++)
953 Kcrypt[i] = kctx->Ksess[i] ^ 0xf0;
954
955 err = crypto_hash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
956 if (err)
957 goto out_err;
958
959 sg_init_table(sg, 1);
960 sg_set_buf(sg, zeroconstant, 4);
961
962 err = crypto_hash_digest(&desc, sg, 4, Kcrypt);
963 if (err)
964 goto out_err;
965
966 /* Compute final Kcrypt from the seqnum and intermediate Kcrypt */
967 err = crypto_hash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
968 if (err)
969 goto out_err;
970
971 seqnumarray[0] = (unsigned char) ((seqnum >> 24) & 0xff);
972 seqnumarray[1] = (unsigned char) ((seqnum >> 16) & 0xff);
973 seqnumarray[2] = (unsigned char) ((seqnum >> 8) & 0xff);
974 seqnumarray[3] = (unsigned char) ((seqnum >> 0) & 0xff);
975
976 sg_set_buf(sg, seqnumarray, 4);
977
978 err = crypto_hash_digest(&desc, sg, 4, Kcrypt);
979 if (err)
980 goto out_err;
981
982 err = crypto_blkcipher_setkey(cipher, Kcrypt, kctx->gk5e->keylength);
983 if (err)
984 goto out_err;
985
986 err = 0;
987
988out_err:
989 crypto_free_hash(hmac);
990 dprintk("%s: returning %d\n", __func__, err);
991 return err;
992}
993